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Texas Instruments SN74CBT3251RGYR
- Part No.:
- SN74CBT3251RGYR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
SN74CBT3251RGYR.pdf
- Description:
- IC MUX/DEMUX 1 X 8:1 16VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,924
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Product details
Overview
SN74CBT3251RGYR from Texas Instruments is a 1-of-8 FET multiplexer/demultiplexer in a 16-pin VQFN package, featuring 5-Ω typical on-state resistance at 5 V, TTL-compatible control inputs (S0–S2, OE), and bidirectional signal routing between common port A and eight B ports (B1–B8). It operates across –40°C to +85°C and supports high-speed digital signal gating in microcontroller I/O expansion.
For engineers reviewing the SN74CBT3251RGYR datasheet, SN74CBT3251RGYR pinout, SN74CBT3251RGYR application, or SN74CBT3251RGYR equivalent, key selection criteria include its low Ron, sub-1 ns propagation delay, 5-V supply compatibility, and VQFN thermal performance (RθJA = 39°C/W) - critical for compact, high-density logic interface designs.
Technical Context
The SN74CBT3251RGYR implements an integrated CMOS FET switch matrix with on-chip binary decoding of S0/S1/S2 to select one of eight bidirectional channels between A and Bx ports. Its active-low OE enables/disables all switches simultaneously, ensuring clean signal isolation when disabled.
Designed for TTL-level control logic, it accepts VIH ≥ 2 V and VIL ≤ 0.8 V while driving loads up to 128 mA per channel. The device uses no internal level shifters - analog signal swing is limited to 0 V to VCC, with no rail-to-rail capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical at VCC = 5 V - ensures minimal voltage drop and signal attenuation in high-speed data paths. |
| Propagation delay (tpd) | 0.24 ns at VCC = 5 V - enables sub-nanosecond switching for timing-critical GPIO expansion. |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5-V logic systems and tolerant of minor rail variation. |
| Operating temperature | –40°C to +85°C - qualified for industrial-grade embedded and automation applications. |
| Input capacitance (Ci) | 3.5 pF - minimizes loading on control lines, preserving signal integrity in dense PCB layouts. |
| Off-state capacitance (Cio) | 4 pF (B port), 17.5 pF (A port) - reduces crosstalk and capacitive coupling between inactive channels. |
| ESD rating (HBM) | ±1500 V - meets standard handling requirements without additional protection circuitry. |
Pinout & Package
VQFN-16 (RGY) package, 3.5 mm × 4.0 mm body, 0.5-mm pitch, exposed thermal pad. Pin 1 marked via top-side index area; pin 6 is NC (no internal connection).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (B4) | I/O port | Bidirectional channel 4 - connects to A when S2:S1:S0 = 000; shares same Ron and bandwidth as other Bx ports. |
| 5 (A) | Common I/O | Shared terminal for all 8 channels - serves as input during demux mode or output during mux mode. |
| 7 (OE) | Enable input | Active-low global switch control - drives all channels into high-impedance state when high. |
| 9–11 (S2, S1, S0) | Binary address inputs | Selects channel B1–B8 per Table 1; TTL-compatible thresholds ensure reliable decoding from MCU GPIOs. |
| 16 (VCC) | Power supply | Single 4–5.5 V supply powers all switches and logic - requires local 0.1-μF bypass capacitor. |
| 8 (GND) | Ground reference | Return path for signal and supply currents - must be low-impedance to minimize ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Low on-state resistance | 5 Ω typical at 5 V - preserves signal amplitude and rise/fall times in high-frequency digital paths. |
| TTL-compatible control inputs | VIH ≥ 2 V, VIL ≤ 0.8 V - eliminates need for level shifters when driven by legacy 5-V MCUs or CPLDs. |
| Low crosstalk | < –60 dB typical - prevents interference between adjacent B ports during simultaneous switching. |
| Fast enable/disable timing | ten = 1.6 ns, tdis = 2.3 ns at 5 V - supports rapid channel reconfiguration in time-multiplexed systems. |
| VQFN thermal performance | RθJA = 39°C/W - enables higher sustained current density than SOIC/SSOP variants under same PCB layout. |
Applications
| Keypad Scanning | MCU GPIO Expansion |
|---|---|
Use Scenario: Microcontroller scans mechanical keypad matrix using single input line and 3-bit address bus. IC Role / Device Role / Timing Role: SN74CBT3251RGYR acts as 1-of-8 analog switch, routing each row/column to MCU ADC or GPIO for polling. Use Value: Reduces required MCU pins from 16 (8×2) to 4 (A, S0–S2), while maintaining sub-microsecond response due to 0.24 ns tpd. |
Use Scenario: Low-cost MCU with limited GPIO count interfaces with multiple peripherals (sensors, LEDs, UARTs). IC Role / Device Role / Timing Role: SN74CBT3251RGYR provides time-shared access to shared data bus, controlled by firmware-addressed S0–S2. Use Value: Enables 8 peripheral connections over one bidirectional data line, with 5-Ω Ron minimizing signal degradation at 10+ MHz toggle rates. |
| Factory Automation I/O Hub | Digital Radio Signal Routing |
Use Scenario: PLC module routes discrete sensor signals (limit switches, photoeyes) to centralized controller. IC Role / Device Role / Timing Role: SN74CBT3251RGYR functions as fault-isolated signal selector, with OE used for safety shutdown. Use Value: Supports industrial ambient (–40°C to +85°C) and withstands 128 mA per channel - sufficient for 24-V optocoupler inputs via level-shifting resistors. |
Use Scenario: Software-defined radio board selects between antenna paths, filters, or ADC inputs in real time. IC Role / Device Role / Timing Role: SN74CBT3251RGYR serves as RF-adjacent baseband signal router, switching IF signals below 100 MHz. Use Value: 5-Ω Ron and <4 pF off-capacitance preserve signal integrity and minimize insertion loss in 50-Ω systems up to 50 MHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3257RGYR | 4-channel (2×1) vs. 8-channel (1×8); identical Ron (5 Ω), package (VQFN-16), and supply range. | Lower channel count suits simpler I/O expansion; lacks S2 input and B5–B8 ports. | Choose when only four bidirectional paths are needed - saves firmware complexity and PCB routing. |
| TS3A27518ERTER | 10-channel, 3.3-V only (1.65–3.6 V), lower Ron (0.7 Ω), but incompatible with 5-V logic levels. | Requires level translation for 5-V MCU interfacing; optimized for portable, battery-powered systems. | Prefer for new 3.3-V designs prioritizing ultra-low Ron and power; not drop-in for existing 5-V SN74CBT3251RGYR layouts. |
Compared with SN74CBT3251RGYR, SN74CBT3257RGYR offers half the channel count in identical packaging and voltage range - ideal for space-constrained 4-signal routing. TS3A27518ERTER delivers superior Ron and lower voltage operation but mandates system-level voltage adaptation, limiting direct replacement in legacy 5-V applications.
Availability
SN74CBT3251RGYR is available at Aetrix Electronics and suitable for factory automation I/O hubs, digital radio signal routing, and MCU GPIO expansion requiring stable component supply, industrial temperature support, and VQFN thermal efficiency.
Supply support for SN74CBT3251RGYR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and broad design support.
The SN74CBT3251RGYR belongs to TI's CBT (Crosspoint Bus Transceiver) family, engineered for high-speed, low-distortion signal routing in industrial and communications equipment where TTL compatibility and minimal propagation delay are essential.
FAQ
What is the maximum continuous current rating per channel for the SN74CBT3251RGYR?
The SN74CBT3251RGYR supports up to 128 mA continuous channel current, as specified in Absolute Maximum Ratings. This value applies to any individual Bx–A path under steady-state conditions at TA ≤ 85°C and must not be exceeded to avoid thermal overstress or parametric shift. Derating is required above 85°C ambient per RθJA = 39°C/W.
Does the SN74CBT3251RGYR support rail-to-rail analog signal switching?
No, the SN74CBT3251RGYR does not support rail-to-rail analog switching. Its analog signal range is strictly 0 V to VCC (4–5.5 V), with no capability to pass voltages beyond those rails. Exceeding VCC or going below GND risks latch-up or damage, as confirmed by VI absolute maximum ratings of –0.5 V to 7 V.
Can the SN74CBT3251RGYR be used with 3.3-V control signals?
No - the SN74CBT3251RGYR requires TTL-compatible control inputs: VIH ≥ 2.0 V and VIL ≤ 0.8 V at VCC = 4–5.5 V. A 3.3-V logic high may fall below guaranteed VIH margin depending on noise and tolerances; use a level shifter or buffer if interfacing with 3.3-V controllers.
Is pin 6 (NC) on the SN74CBT3251RGYR electrically isolated or internally connected?
Pin 6 on the SN74CBT3251RGYR is designated NC (No Connect) and is electrically isolated - no internal bond wire or silicon connection exists. It must remain unconnected on the PCB; routing traces or vias to this pad violates TI's recommended layout and may cause mechanical stress or solder wicking issues.
What is the thermal resistance (RθJA) of the SN74CBT3251RGYR, and how does it compare to other packages?
The SN74CBT3251RGYR has RθJA = 39°C/W, measured per JESD 51-5. This is significantly lower than SOIC (73°C/W), SSOP (82–90°C/W), and TSSOP (108°C/W) variants - enabling higher power dissipation or smaller thermal margins in compact, thermally constrained designs.
SN74CBT3251RGYR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Multiplexer/Demultiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-VQFN (4x3.5)
SN74CBT3251RGYR FAQ
1.How can I place an order for SN74CBT3251RGYR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3251RGYR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74CBT3251RGYR reliable?
The price and inventory of SN74CBT3251RGYR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3251RGYR is usually 5 days.
3.What payment methods are accepted for SN74CBT3251RGYR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3251RGYR transactions.
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4.How is shipping managed for SN74CBT3251RGYR?
SN74CBT3251RGYR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3251RGYR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74CBT3251RGYR?
For technical support, including SN74CBT3251RGYR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3251RGYR requirements.
6.How does Aetrix verify that SN74CBT3251RGYR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3251RGYR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74CBT3251RGYR meets industry standards.
7.What is the process for return or replacement of SN74CBT3251RGYR?
All SN74CBT3251RGYR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3251RGYR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74CBT3251RGYR part is unused and in its original packaging.
Return procedure for SN74CBT3251RGYR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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